Drawing frame-roving frame combination for the production of rove by means of a pneumatic spinning process

ABSTRACT

The invention relates to a Drawing-Frame-slubbing machine combination ( 35 ), with which, in the same machine, several fibre assemblies ( 38 ) are first doubled and stretched and a roving yarn ( 9 ) is then manufactured from this. The manufacture of the roving yarn ( 9 ) takes place in that a twist (rotation) is applied to the drafter sliver ( 3 ), whereby the twist application is effected by means of one or more air flows. To achieve this, the device ( 35 ) according to the invention exhibits a drawing frame ( 36 ) and one or more twist application means ( 4 ) arranged downstream of this.

The present invention relates to a drawing-frame-slubbing-machine-combination for the doubling and drafting of several fibre assemblies to form a drafter sliver or sliver and for the subsequent manufacture of a roving yarn from the sliver, as well as a method for the manufacture of a roving yarn in accordance with the preamble to the independent Patent claim 11.

A combined device of this type is unknown in the textile technology. The two individual construction groups of which the device according to the invention consists are, however, familiar to the technical sector in their parts, i.e. not in this form and not with the twist application method according to the invention. The drawing frame as a textile machine for the doubling and drafting of several fibre assemblies to form one sliver is known as such. Slubbing machines for the manufacture of what are known as roving yarns from one or more slivers are indeed also known as such, but not with the twist application element according to the invention. The slubbing machines according to the present invention include, for example, what is known as the speed frame or roving frame. The roving yarn serves as the supply material for the actual spinning process, i.e. for the spinning of the fibres to make a fibre yarn, for example on a ring-spinning machine.

The fibre assemblies coming from the preliminary system (carding room) are, according to the prior art, first doubled with the aid of drawing frames and at the same time stretched or drafted, and then deposited in cans. The sliver which results from this is then presented to the slubbing machines (speed frames) for further processing. The sliver is in the first instance subjected as a rule to further stretching or drafting in an individual drafting assembly, and then slightly twisted by the application of twist, before the original fibre assembly is wound up as roving yarn on a roving yarn bobbin.

The roving yarn derived in this way (also referred to as fibre slubbing, flyer slubbing, flyer yarn or generally slubbing) usually serves as a presentation material for ring-spinning machines. The slubbing machine, as mentioned, usually exhibits its own drafting device, in most cases a double apron draft system. After being drawn through the drafting device of the slubbing machine, the roving yarn undergoes a slight twist (referred to as a protective twist), in order for the slubbing produced by this to exhibit a certain strength so that it can be wound on a bobbin and will not disintegrate. The twist which is applied must only be sufficiently great for the roving yarn to be held together for the winding up and later unwinding and the transport of the bobbins, in order in particular for no false drafts to occur (thin places in the roving yarn). The twist must be easy to release, and the roving must be capable of being drawn, in order for the subsequent spinning process, e.g. in a ring-spinning machine, to be put into effect.

As a slubbing machine, use is usually made of what is known as a speed frame or roving frame, which manufactures the correspondingly-named flyer slubbing. This slubbing machine is equipped with a drafting device and a spindle for winding up the flyer slubbing onto a cylinder bobbin by means of a flyer to support the slubbing against the centrifugal force incurred by the bobbin revolutions. The speed frame is an expensive machine in the spinning process as a whole, in particular due to the complicated winding mechanism. Added to this is the fact that the usual output from a speed frame is about 20-25 metres of roving yarn per minute. This low production cannot be increased with regard to the winding system with flyers, however, since a higher speed is limited by the centrifugal force, which the flyers and roving yarn bobbin must withstand.

Accordingly, attempts have already been made to circument the slubbing machine by what is referred to as direct spinning or sliver-to-yarn spinning, where the sliver is being delivered directly as supply material for the ring-spinning machine. However, the high draft produced by what is referred to as sliver direct spinning only achieves the result to a restricted degree which is obtained with the supply of a flyer slubbing on the ring spinning machine. This applies in particular if fine yams with Nm 50 and finer are being spun. In addition, the supply of drafting cans with ring-spinning machines is elaborate and complicated.

One possibility for replacing a speed frame is disclosed in the printed specification EP 375 242 A2. This describes a machine for the manufacture of a roving yarn from a fibre assembly, which has a twist application means with a rotating rotor. The rotor exhibits a continuous longitudinal hole on its axis of rotation, through which the fibre assembly which is to be twisted is guided. The rotor has at a specific height several holes rotationally symmetrically arranged in the radial direction. These radial holes connect the longitudinal hole, through which the fibre assembly is guided, with the outer surface of the rotor. This outer surface of the rotor is subjected to a vacuum or a strong under-pressure. If the fibre assembly is now drawn through the longitudinal hole, individual free fibre ends are sucked off the surface of the fibre assembly into these radial holes. In operation, the rotor rotates while the fibre assembly is drawn through the longitudinal hole. The fibre ends located in the radial holes are in this way wound around the moving fibre assembly, as a result of which a twist (true twist) is applied to the fibre assembly or its individual fibres

The device according to the mentioned publication is relatively expensive in manufacture and operation due to the mechanical elements (rotating rotor) and the vacuum technology.

For the manufacture of yarns it is known, for example from DE 32 37 989 C2, of drawing a fibre slubbing or drawing sliver in a drafting device and then applying a twist to the drawn fibre assembly, whereby the application of the twist is effected by air jets in two sequential twist chambers. The application of the twist in the first pneumatic twist chamber is effected in counter-direction to the further following twist application in the second pneumatic twist chamber (the first twist application causes, for example, a left-hand rotation, while the following twist application in the second twist chamber causes a right-hand rotation). In this way a yarn is produced in accordance with what is known as the false twist spinning process).

According to Patent Specification CH 617 465, a false twist nozzle is used for the manufacture of a staple fibre yarn (likewise a false twist spinning process).

During the production of a yarn, i.e. during a spinning process, the individual fibres are spun or twisted with one another sufficiently strongly for the twisting to be quasi-irreversible, and the yarn produced also cannot be drawn any further. The strengthening achieved by the twisting is also necessary for the yarn, since only in this way it will obtain the necessary high tensile strength, The consequence of this, however, is that the devices and spinning processes referred to are not suitable for forming a roving yarn. The roving yarn exhibits only what is referred to as a protective twist, which must not impede the further spinning processes on the following machines (e.g. drafting at the ring-spinning machines); i.e. the roving yarn must remain capable of being drawn or drafted. The devices described in these two publications are therefore only suitable for the manufacture of yarns and not of roving yarn capable of drafting.

The object of the present invention is to provide a stubbing machine and a method for the manufacture of a roving yarn, with which the process can be shortened and the disadvantages referred to heretofore of conventional slubbing machines can be avoided. In particular, it is intended that a roving yarn should be manufactured which exhibits the characteristics of conventional flyer slubbings or roving yarns respectively, with regard in particular to the drafting capability of the roving yarn which is manufactured.

This object is resolved by the features in the independent claims 1, 2, and 11. By the combination of a drawing frame with a slubbing machine with twist application means according to the invention it is possible for the disadvantages of the prior art to be circumvented, i.e. in particular to shorten the process and provide a slubbing machine which allows for a higher production capacity.

Advantageous embodiments and designs of the invention are to be found in the Sub-Claims.

The invention, the idea of the invention, and the means of effect of the invention are explained hereinafter on the basis of embodiments represented in figures. Attention should expressly be drawn to the fact, however, that the invention and the idea of the invention are not restricted to the embodiments shown in the examples.

FIG. 1 shows a drawing-frame-slubbing machine combination 35 according to the invention. This machine can be divided schematically into two sections, I and II. The first section I contains the drafting device 36 with a drafting unit 37. The drafting unit 37 is preferably regulated The fibre assemblies 38, which are taken from several cans 39, are doubled before the drafting device and stretched in the drafting unit 37. The drafter sliver 3 which results is then conducted directly to the section 11 of the drawing-frame-slubbing machine combination according to the invention. In sector 11 and at the spinning positions 1 respectively, a roving yarn 9 is manufactured from the drafter sliver 3. For this purpose, the drafter sliver 3 runs through a twist application means 4 and preferably a drafting device 2 arranged upstream of the twist application means 4. The roving yarn 9 is then wound up by a winding device 7. The means of function of the twist application means 4 is described in the Figures which follow.

FIG. 1a shows in diagrammatical form a possible spinning position 1 (i.e. twist application point) of a drawing-frame-slubbing machine combination (whole machine not shown), according to the invention. The Figure shows only one of several possible embodiments for the twist application means 4 The drawing-frame-slubbing machine combination according to the invention can also be equipped with twist application means which operate according to another air-spinning process. The embodiment of the spinning position 1 shown exhibits a drafting device 2 (likewise represented diagrammatically), which is 'supplied with a drafter sliver 3 (e.g. a doubled drafter sliver). The (drafted) fibre assembly 3 passes from the drafting device 2 into the twist application means 4. In the twist application means 4 the drafter sliver 3 is twisted to form a roving yarn 9, i.e. the drafter sliver is at least partially subjected to a true twist (i.e. at least a part of the fibres of the drafter sliver). In addition to this, FIG. 1a shows a pair of delivery rollers 8 with a nip line 34 and a winding device/take-up motion 7 (likewise represented diagrammatically) for the roving yarn 9. The device according to the invention does not necessarily need to exhibit a drafting device 2 or a pair of delivery rollers 8, as is represented in FIG. 1a.

The twist application means 4 shown in FIG. 1a operates according to what is referred to as the vortex process, a special air-spinning method. The vortex air-spinning method is known as a yarn spinning process. As already described heretofore, devices for the forming of yarn are as a rule unsuitable for the manufacture of a draftable roving yarn. Surprisingly and unexpectedly, experiments with suitably modified air-spinning devices have revealed that certain air-spinning processes are also suitable for the manufacture of roving yarns. To achieve this, however, the dimensions and flow circumstances of conventional yarn air-spinning devices must be adapted. The twist application means according to the invention need only apply a protective twist to the drafter sliver in order for the stubbing or roving yarn thereby formed to remain capable of being drafted. Conventional air-spinning devices rotate the drafter sliver in such a way that a yarn or thread is formed which is strongly twisted in such a way that the twist is irreversible, and, in particular, is no longer capable of being drafted. By providing correspondingly larger dimensions for the air-spinning devices, as well as an adjustment of the flow characteristics, and in particular by suitably high delivery speeds, it is possible, with air-spinning devices also roving yarns or slubbings capable of being drawn or drafted to be manufactured The most suitable characteristics can best be determined experimentally.

According to initial experiments, air-spinning devices for roving yarns exhibit preferably one or more of the following properties:

Preferably, the diameter of the twist or swirl chamber amounts to at least 5 mm (see swirl chamber 5 in the Figures described hereinafter);

Preferably, the delivery speed of the drafter sliver (from the delivery rollers of the drafting device) amounts to at least 200 m/min;

Preferably, the pressure of the air flow, before it flows out through the nozzle holes or nozzles into the swirl chamber, amounts to a maximum of 5 bar (see air flow 32, 16, 16.1, 16.2, or 20, as well as nozzle holes or nozzles 11 in the Figures described hereinafter);

Preferably these air-spinning devices administer a deep winding rotation to the roving or slubbing respectively, and preferably the winding rotation or coefficient of rotation alpha_(m) is less than 70.

The mode of effect of the device according to the invention for the formation of a roving yarn structure is similar to that of conventional air-spinning processes for the formation of yarn. For this reason, the air-spinning processes used for the device according to the invention are not considered here in any great detail. By contrast with conventional air-spinning devices, with the devices and methods according to the invention, only a protective twist is applied to the drafter sliver and the roving yarn respectively. This protective twist is of such a nature that the roving yarn remains capable of being drawn for the further processing procedure. To form the roving yarn, the drafter sliver is subjected at least in part to a true twist, i.e. at least a part of the fibres of the drafter sliver, if not all, receive a true twist (rotation) by means of an air flow. This true twist or rotation is, as mentioned, only a protective twist. The roving or slubbing manufactured according to the invention therefore has the same properties as a slubbing manufactured with a conventional speed frame.

The remarks just made naturally also apply to all twist application means of this specification according to the invention, which are illustrated and explained hereinafter on the basis of further figures. These remarks accordingly apply not only to the twist application means 4 from FIG. 1a, but also to those twist application means with the reference FIGS. 15, 17, 18, and 31.

One of the possible twist application means according to the invention for the formation of roving yarn is the object 4 from FIG. 1a, which, as already mentioned, operates according to what is known as the vortex air-spinning process. The device 4 exhibits for this purpose a fibre guide element 10, with which the drafter sliver 3 is delivered into the swirl chamber 5 of the twist application means 4. In the swirl chamber 5 a fluid device, not represented in greater detail, creates an air flow 32 or a swirl flow, by means of one or more nozzle holes 11. The swirl flow caused by this inside the swirl chamber 5 causes the individual free fibre ends 12 on the surface of the drafter sliver 3 to lie around the inlet aperture 13 of the roving formation element 6, and, taken up by the rotating swirl flow in the swirl chamber, to rotate around the core 14 of the drafter sliver. As a result, the drafter sliver 3 in the swirl chamber 5 is subjected at least partially to a true twist by means of an air flow 32. This means that at least a part of the drafter sliver, i.e. individual fibres, is subjected to a true twist around a core of fibres remaining largely parallel. The roving yarn 9 which is formed at the inlet aperture 13 is drawn off, for example, by a pair of delivery rollers 8 and wound up onto a winding device 7. To do this, the roving formation element 6 exhibits a hole (see FIG. 1a). The winding device 7 in FIG. 1a is represented in diagrammatic form only. For example, the winding device can be a cross winder, a precision cross-winder, a random cross-winder, a stepped cross-winder, or a parallel winder.

FIG. 2 shows the twist application means 4 from FIG. 1a in another view. In this illustration it can be particularly readily seen how the drafter sliver 3 is guided by the fibre guide element 10 into the swirl chamber 5, where a swirl air flow created by the nozzle holes 11 takes up the free fibre ends 12 of the drafter sliver 3 and lays them around the inlet aperture 13 of the roving yarn formation element 6. The free fibre ends 12 lying around the inlet aperture 13 form a “sun” rotating around the core 14 of the drafter sliver. The free fibre ends 12 accordingly rotate about the core 14 of the drafter sliver, as a result of which the drafter sliver 3 receives at least in part a true twist (rotation) in the swirl chamber 5 as a result of the air flow. The roving yarn 9 which is formed as a result at the inlet aperture 13 is drawn through (see arrow) by the roving yarn formation element 6 (e.g. a spindle, as represented here).

FIG. 3 shows a further rotation application means 15 according to the invention. This operates in accordance with what is referred to as the single-nozzle false twist process and does not exhibit a roving yarn formation element. The twist application means 15 (represented diagrammatically) likewise exhibits only one swirl chamber 5, in which an air flow 16 (swirl flow) is created by means of one or more nozzle openings 11. By means of this air flow 16 the drafter sliver is subjected at least partially to a true twist in the swirl chamber 5.

The true twist application (true twist in the drafter sliver) is represented in FIG. 3a. Inside the swirl chamber 5 a rotation is applied to the drafter sliver by the air flow 16, i.e. at least a part of the fibres of the drafter sliver 3 are rotated/twisted, so that the slubbing 9 is formed.

FIG. 3b shows a variant of the twist application means according to FIG. 3a. The twist application means 17 exhibit two swirl chambers 5, which in each case do not contain a roving yarn formation element. The true twist is applied in this case too by means of one, or in this case two, air flows 16.1 and 16.2. At least a part of the fibres of the drafter sliver 3 receive a true twist (rotation). In this case too, the roving yarn 9 and the slubbing are drawn off and wound up by a device which is not represented. Preferably, the twist application means 17 exhibit several nozzle holes 11. The nozzle holes 11 serve to produce the air flows 16.1 and 16.2. The nozzle holes are aligned in such a way that the emerging air jets jointly and together create in each case the air flow 16.1 and 16.2 respectively. For this purpose the inlet angles of the nozzle holes 11 are preferably the same inside the individual swirl chamber 5. The air flows 16.1 and 16.2 are also directed in the same way, i.e. such that the two air flows 16.1 and 16.2, despite separate swirl chambers, have the same direction of rotation (right or left rotating air flow).

FIG. 3c shows a variant of the twist application means according to FIG. 3b. The twist application means 40 differ from the previous device in that the air flows 41 and 42 in the swirl chambers 5.1 and 5.2 are not in the same direction but are in opposite directions (i.e. one air flow 41 is right-rotating and the other 42 is left-rotating). As a result, the drafter sliver 3 is subjected to a twist according to what is referred to as the false twist process.

Preverably the individual nozzles or nozzle holes are arranged rotationally symmetrically to one another in all embodiments of the invention.

Preferably the twist application means according to the invention also exhibit one or more twist jamming or twist stop elements. Twist jamming elements can exhibit different forms; a twist jamming element can be formed, for example, as an edge, a pin, a toroidal surface, a cone, or in the form of several deflecting means.

FIG. 4 shows a twist application means 18 with a twist jamming element in the form of a pin 19. The remaining elements in FIG. 4 correspond largely to the embodiments already described and also exhibit accordingly the same reference numbers. The pin 19 in FIG. 4 serves both as a twist jamming element as well as a false yarn core. Twist jamming elements serve to prevent a rotation in the drafter sliver being propagated further rearwards. In particular, this prevents any possible false twist occurring, and therefore prevents any true twist being applied to the drafter sliver. The use of twist jamming elements for the devices and method according to the invention is not absolutely necessary, but is recommendable. In particular, the true twist application by means of the air flow is improved. A twist jamming element is not absolutely necessary with those devices according to the invention with which the twist application takes place according to a false twist process.

As is shown in FIGS. 4a and 4b, a pin 19 prevents the twist incurred by the airflow from propagating further to the rear in the direction of the inlet of the fibre guide element in the drafter sliver 3. This can be seen particularly well in FIGS. 4a, 4b, and 4c. The air flow 20 around the mouth of the roving yarn formation element (not shown) creates a rotation or a twist respectively inside the drafter sliver 3. Due to the presence of the pin 19 as a twist jamming element, it is prevented that the rotation of the fibres is transferred onto the drafter sliver 3, which is lying on the fibre guide element 10 and 21 respectively (see parallel non-twisted fibres on the fibre guide elements 10 and 21 respectively in the Figures).

A toroidal fibre guide surface 21 can also serve as a twist jamming element. FIG. 4b shows a toroidal fibre guide surface 21, which additionally exhibits a pin 19. As a result, the twist jamming function is particularly effective. A toroidal fibre guide surface 21 with pin is also represented in FIG. 4c. The elements in FIG. 4c correspond largely to the elements in FIG. 4b, with the difference that the pin 19 in FIG. 4c is truncated.

FIG. 5 shows a fibre guide element 10 with what is referred to as a twist stop cone 24. The twist stop cone 24 fulfils the function of the twist jamming element. The means of effect is the same as with the pin 19; Cone or pin also serve as what are referred to as false yarn cores. The fibres or drafter sliver lie in spiral fashion around the false yarn core, as a result of which the propagation of the rotation against the drawing direction of the roving yarn or drafter sliver is prevented.

It is also possible for only one toroidal fibre guide element 22 without pin to serve as a twist jamming element. This is represented, for example, in FIG. 6 (compare with FIG. 4c). A toroidal fibre guide surface is may be sufficient as a twist jamming element. The additional use of a pin is not absolutely necessary. Different views of a toroidal fibre guide element without pin 22 are shown in FIGS. 6a and 6b.

It is also possible for only an edge 33 to serve as a twist jamming element, which does not necessarily have to be accompanied by a toroidal fibre guide surface, with the result that a flat fibre guide surface can also be sufficient.

FIG. 7 shows further twist jamming elements which could be used in the device according to the invention. The Figure shows a fibre guide element 23 with several deflection means. These deflection means 26 have the function, in addition to deflecting the drafter sliver 3, also to act as a twist stop. It can be readily seen in the Figure how the deflection means 26 take effect with a twist jamming function. The drafter sliver is drawn in the non-twisted state in the direction of the roving yarn formation element 6. At the mouth of the roving yarn formation element 6 the free fibre ends 12 are rotated by the air flow 20 of the swirl chamber by means of true twist application. The rotation of the free fibre ends 12 causes a torsion moment, which tries to propagate against the draw-off direction (arrow) of the roving yarn in the drafter sliver 3. Due to the presence of the deflection means 26 with twist jamming function, this torsion moment or rotation, which would cause the torsion moment in the drafter sliver, is held up or stopped. This means that no rotation propagates into the drafter sliver 3 (see representation in FIG. 7; the drafter sliver 3 is not twisted). In this way a true twist (rotation) is applied to the drafter sliver 3 by means of the air flow 20, as a result of which the roving yarn 9 comes into being.

Without the deflection means 26 with twist jamming function, the rotation would propagate into the drafter sliver 3, as a result of which what is referred to as a false twist would occur, which under certain circumstances prevents a true twist of the drafter sliver or the roving yarn respectively. A further representation of the circumstances just explained can be seen in FIG. 7a: Here too it can readily be seen how the drafter sliver 3 remains untwisted thanks to the deflection means 26.

FIGS. 8a and 8b show deflection means with twist jamming function of different forms. FIG. 8c shows a view of the deflection means 27 and 28 respectively in the draw-off direction of the roving yarn or the drafter sliver respectively. Different forms for the deflection means with twist jamming function can be conceived. The deflection means 26, 27 and 28 shown represent only some of the possible forms.

The stubbing machine according to the invention can preferably also exhibit means which determine the width of the drafter sliver before running into the twist application means. These means may be, for example, funnels or other forms of condensers. Such a means 29 is shown in FIG. 9. The Figure shows a funnel 29 which restricts a drafter sliver 3 in its width and leads it to a twist application means 31. Such a funnel 29 or other condenser can be arranged downstream of a delivery roller pair 30. The delivery roller pair 30 is shown in a plan view. The reference number 34 indicates the nip line of the delivery roller pair 30.

As described heretofore with regard to the embodiments, the drawing-frame-slubbing machine combination according to the invention contains a special twist application means for the manufacture of a roving yarn from a drafter sliver. The special twist application means of the device according to the invention twists a fibre band or sliver to form a roving yarn. For this purpose the twist application means according to the invention exhibit a swirl chamber with a roving yarn formation element contained within it. Preferably the roving yarn formation element is a spindle. According to the invention, in the swirl chamber of the twist application means a true twist (rotation) is applied to the drafter sliver at least partially (i.e. to at least a part of the fibres) by means of an air flow.

The slubbing machine according to the invention, for the manufacture of a roving yarn from a drafter sliver can also exhibit another form of a twist application means: A further twist application means, likewise according to the invention, exhibits a swirl chamber without roving yarn formation element (e.g. spindle). This swirl chamber exhibits means, however, which allow for an air flow to come into being in the swirl chamber. This air flow applies a true twist (rotation) at least in part to the drafter sliver (i.e. to at least a part of the fibres). This further embodiment of a twist application means according to the invention may also exhibit several swirl chambers with correspondingly several means for the formation of an air flow (see, for example, FIG. 3b or 3c).

Amongst the drawing frame a drafting device can in each case be additionally arranged upstream the twist application means or the stubbing machine according to the invention.

Preferably, the twist application means according to the invention have in each case one or more twist jamming elements. These twist jamming elements can be designed, for example, as edges, pins, as toroidal surfaces, as cones, or as several deflection means. The twist application means according to the invention can also exhibit a combination of the twist jamming elements just referred to, such as a toroidal surface with a pin, or a cone with a pin, or an edge with a pin, or a toroidal surface with a pin. The twist application means according to the invention can exhibit several of these twist jamming elements or a combination of them.

Preferably, the twist application means according to the invention exhibit several nozzles for the production of the air flow, whereby the nozzles are aligned in such a way that the air jets emerging from them are arranged in the same direction in order to create together an air flow in the same direction inside the same swirl chambers. This does not necessarily apply in situations in which several swirl chambers are present. If several swirl chambers are present, the air flows can exhibit opposed directions of rotation. Preferably, the nozzle holes are arranged rotationally symmetrically inside a swirl chamber around the axis of the swirl chamber (the entry angles of the nozzle holes are therefore the same). If several swirl chambers are present, the nozzles can preferably be arranged in such a way that the nozzles of an individual swirl chamber are indeed arranged rotationally symmetrically, but each swirl chamber exhibits a different entry angle for the individual nozzles The air jets emerging in the individual swirl chambers can therefore exhibit not only different directions of rotation, in the sense of a left or right rotation, but also have different “rise angles”.

A rotationally-symmetrical arrangement of the nozzles is shown, for example, in FIG. 2. A rotationally-symmetrical offset arrangement of the nozzles can be seen in FIG. 3b (the nozzle holes 11 of the two swirl chambers are, by analogy with FIG. 2, also arranged rotationally symmetrically).

Preferably, the stubbing machines and twist application means according to the invention exhibit a means, in particular a funnel or an aerodynamic or mechanical condenser, which has the function of determining the width of the drafter sliver before it runs into the twist application means.

Preferably, the distance interval between the intake aperture of the roving yarn formation element (e.g. spindle) and the last nip lie (e.g. of the pair of delivery rollers) is not greater than the longest fibre length obtained in the drafter sliver or greater than the mean staple fibre length of the drafter sliver.

Preferably, the distance interval between the inlet of the twist application means and the last nip line (e.g. of the delivery roller pair of a drafting device) is not greater than the longest fibre length obtained in the drafter sliver.

Preferably, a winding device is allocated to the slubbing machine according to the invention. This winds up the roving yarn emerging from the twist application means. Preferably, the winding device is a cross-winder, a precision cross-winder, a random cross-winder, a step precision cross-winder, or a parallel winder.

Preferably, the yarn formation element is a spindle.

The invention also includes an inventive method for the manufacture of a roving yarn from a drafter sliver. With this method according to the invention, a drafter sliver is manufactured from several fibre assemblies by doubling and stretching whereby the drafter sliver is then preferably stretched again and then again subjected at least in part (i.e. at least a part of the fibres of the drafter sliver) to a twist application (rotation).

For this method according to the invention, preferably several nozzles are present for the production of the air flow. For this purpose the nozzles are preferably arranged rotationally symmetrically around one axis in the swirl chamber or rotationally symmetrically offset around a axis (see explanations above and FIGS. 2 and 3b, 3c).

With the stubbing machine according to the invention as discussed heretofore, in particular speed frames, with the use according to the invention of a twist application means or with the method according to the invention for the manufacture of a roving yarn, only a protective twist is applied; i.e. the roving yarn produced by the air flow is capable of being drafted.

The invention is not restricted to the explicitly cited possibilities and embodiments. Rather, these variants are intended to be incentives for the person skilled in the art to implement the idea of the invention in as favourable a manner as possible. Accordingly, further advantageous embodiments and combinations can be easily derived from the embodiments described and shown in the Figures, which likewise reproduce the thinking of the invention and should be protected by this Application. Some of the disclosed features of the invention have been described as combined in this Description, and will be claimed as combined in the following Claims. It is also conceivable, however, for individual features of the invention to be claimed alone or in another combination in application of the thinking of the invention. The Applicants therefore expressly reserve the right to make provision for other combinations in the use of the thinking of the invention.

LEGEND

-   1 Spinning position of a stubbing machine -   2 Drafting device -   3 Drafter sliver -   4 Twist application means -   5 Swirl chamber -   6 Roving yarn formation element (spindle) -   7 Winding device -   8 Pair of delivery rollers— -   9 Roving yarn -   10 Fibre guide element -   11 Nozzle holes or nozzles -   12 Free fibre ends -   13 Intake aperture -   14 Core -   15 Twist application means without roving yarn formation element -   16, 16.1, 16.2 Air flow -   17 Twist application means with two swirl chambers -   18 Twist application means with twist jamming element -   19 Pin -   20 Air flow -   21 Toroidal fibre guide element with pin -   22 Toroidal fibre guide element without pin -   23 Fibre guide element with several deflection means -   24 Twist stop cone -   25 Fibre guide element -   26,27,28 Deflection means with twist stop function -   29 Funnel -   30 Pair of delivery rollers -   31 Twist application means -   32 Air flow -   33 Edge -   34 Nip line -   35 Drawing-frame-slubbing machine combination -   36 Drawing frame -   37 Drafting unit -   38 Fibre assembly -   40 Twist application means -   41 Right-rotating airflow -   42 Left-rotating air flow 

1. Drawing-Frame-slubbing machine combination (35) for the doubling and stretching of several fibre assemblies (38) to form a draft sliver (3) and for subsequent manufacture of a roving yarn (9) from the draft sliver (3), containing one or more drawing frames (36), preferably regulated, as well as one or more spinning positions (1) arranged accordingly downstream, having a twist application means (4) and preferably a drafting device (2) arranged upstream of the twist application means (4), characterized in that the twist application means (4) contains a swirl chamber (5) with a roving yarn formation element (6) contained within it, whereby the drafter sliver (3) is subjected in the swirl chamber (5) to a true twist, or at least in part to a true twist, by means of an air flow (32). 2-14. (canceled) 